Fingerprint Sensor Device and Method

ABSTRACT

A fingerprint sensor package and method are provided. The fingerprint sensor package comprises a fingerprint sensor along with a fingerprint sensor surface material and electrical connections from a first side of the fingerprint sensor to a second side of the fingerprint sensor. A high voltage chip is connected to the fingerprint sensor and then the fingerprint sensor package with the high voltage chip are connected to a substrate, wherein the substrate has an opening to accommodate the presence of the high voltage chip.

PRIORITY CLAIM AND CROSS-REFERENCE

This application is a continuation of U.S. patent application Ser. No.16/390,898, filed on Apr. 22, 2019, entitled “Fingerprint Sensor Deviceand Method,” which is a continuation of U.S. patent application Ser. No.15/877,978, filed on Jan. 23, 2018, entitled “Fingerprint Sensor Deviceand Method,” now U.S. Pat. No. 10,268,868, issued on Apr. 23, 2019,which is a divisional of U.S. patent application Ser. No. 15/149,903,filed on May 9, 2016, now U.S. Pat. No. 9,875,388, issued on Jan. 23,2018, entitled “Fingerprint Sensor Device and Method,” which applicationclaims priority to and the benefit of U.S. Provisional Application No.62/300,164, filed on Feb. 26, 2016, entitled “Fingerprint SensorModule,” which applications are hereby incorporated herein by referencein their entirety.

BACKGROUND

As user devices become smaller and more portable, it has become easierfor people with ill intentions to steal user devices. When such devicesbear sensitive information of the user, thieves may be able to accesssuch information unless barriers have been placed into the user device.Once such barrier is a fingerprint sensor which can be used to read thefingerprint of the person attempting to access the device and, if thefingerprint is not the same fingerprint of the user, access may bedenied.

However, as user devices such as cell phones become smaller, there is apressure on each of the individual components within the user device toalso see a concurrent reduction in size. As such, there is a pressure toreduce the size of the fingerprint package that contains the fingerprintsensor without seeing a reduction in performance. As such, improvementsare needed to see the desired reduction in size.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIGS. 1A-1F illustrate a fingerprint sensor package which uses throughvias laterally removed from a sensor in accordance with someembodiments.

FIGS. 2A-2B illustrate an embodiment which uses through vias extendingthrough the fingerprint sensor in connection with a redistribution layerin accordance with some embodiments.

FIGS. 3A-3B illustrate an embodiment which uses through vias extendingthrough the fingerprint sensor without a redistribution layer inaccordance with some embodiments.

FIG. 4 illustrates an incorporation of the fingerprint sensor packageinto a semiconductor device in accordance with some embodiments.

FIG. 5 illustrates an incorporation of the fingerprint sensor packageinto a semiconductor device in accordance with some embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the invention. Specificexamples of components and arrangements are described below to simplifythe present disclosure. These are, of course, merely examples and arenot intended to be limiting. For example, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed between the first and second features, such thatthe first and second features may not be in direct contact. In addition,the present disclosure may repeat reference numerals and/or letters inthe various examples. This repetition is for the purpose of simplicityand clarity and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

Embodiments will now be described with respect to a fingerprint sensorin a system in package (SiP) solution or else an integrated fan out(InFO) structure. However, embodiments may be used in any suitablepackage.

With reference now to FIG. 1A, there is illustrated an embodiment whichutilizes a carrier substrate 101, an adhesion layer 103, a polymer layer105, a first redistribution layer 107, first through substrate vias(TSVs) 109, and a fingerprint sensor 104. In an embodiment the carriersubstrate 101 comprises, for example, silicon based materials, such asglass or silicon oxide, or other materials, such as aluminum oxide,combinations of any of these materials, or the like. The carriersubstrate 101 is planar in order to accommodate an attachment of devicessuch as the fingerprint sensor 104.

The adhesive layer 103 may be placed over the carrier substrate 101 inorder to assist in the attachment of overlying structures to the carriersubstrate 101. In an embodiment the adhesive layer 103 is a die attachedfilm (DAF), such as an epoxy resin, a phenol resin, acrylic rubber,silica filler, or a combination thereof, and is applied using alamination technique. However, any other suitable material and method offormation may be utilized.

The polymer layer 105 is initially formed over the adhesive layer 103.In an embodiment the polymer layer 105 may be made of one or moresuitable dielectric materials such as silicon oxide, silicon nitride,low-k dielectrics such as carbon doped oxides, extremely low-kdielectrics such as porous carbon doped silicon dioxide, combinations ofthese, or the like. The polymer layer 105 may be formed through aprocess such as chemical vapor deposition (CVD), although any suitableprocess may be utilized, and may have a thickness between about 0.5 μmand about 5 μm, such as about 9.25 KÅ

Once the polymer layer 105 has been formed, underbump metallizationlayers 137 and the first redistribution layers 107 may be formed overthe polymer layer 105. In an embodiment the underbump metallizationlayers 137 may comprise three layers of conductive materials, such as alayer of titanium, a layer of copper, and a layer of nickel. However,one of ordinary skill in the art will recognize that there are manysuitable arrangements of materials and layers, such as an arrangement ofchrome/chrome-copper alloy/copper/gold, an arrangement oftitanium/titanium tungsten/copper, or an arrangement ofcopper/nickel/gold, that are suitable for the formation of the underbumpmetallization layers 137. Any suitable materials or layers of materialthat may be used for the underbump metallization layers 137 are fullyintended to be included within the scope of the embodiments.

In an embodiment the underbump metallization layers 137 are created byforming each layer over the polymer layer 105. The forming of each layermay be performed using a plating process, such as electrochemicalplating, although other processes of formation, such as sputtering,evaporation, or PECVD process, may alternatively be used depending uponthe desired materials. The underbump metallization layers 137 may beformed to have a thickness of between about 0.7 μm and about 10 μm, suchas about 5 μm.

In an embodiment the first redistribution layers 107 comprise a seriesof conductive layers 133 (such as two conductive layers) embedded withina series of dielectric layers 135 (such as three dielectric layers). Inan embodiment, a first one of the series of dielectric layers 135 isformed over the polymer layer 105, and the first one of the series ofdielectric layers 135 may be a material such as polybenzoxazole (PBO),although any suitable material, such as polyimide or a polyimidederivative, may be utilized. The first one of the series of dielectriclayers 135 may be placed using, e.g., a spin-coating process, althoughany suitable method may be used.

After the first one of the series of dielectric layers 135 has beenformed, openings may be made through the first one of the series ofdielectric layers 135 by removing portions of the first one of theseries of dielectric layers 135. The openings may be formed using asuitable photolithographic mask and etching process, although anysuitable process or processes may be used to pattern the first one ofthe series of dielectric layers 135.

Once the first one of the series of dielectric layers 135 has beenformed and patterned, a first one of the series of conductive layers 133is formed over the first one of the series of dielectric layers 135 andthrough the openings formed within the first one of the series ofdielectric layers 135. In an embodiment the first one of the series ofconductive layers 133 may be formed by initially forming a seed layer(not shown) of a titanium copper alloy through a suitable formationprocess such as CVD or sputtering. A photoresist (also not shown) maythen be formed to cover the seed layer, and the photoresist may then bepatterned to expose those portions of the seed layer that are locatedwhere the first one of the series of conductive layers 133 is desired tobe located.

Once the photoresist has been formed and patterned, a conductivematerial, such as copper, may be formed on the seed layer through adeposition process such as plating. The conductive material may beformed to have a thickness of between about 1 μm and about 10 μm, suchas about 5 μm. However, while the material and methods discussed aresuitable to form the conductive material, these materials are merelyexemplary. Any other suitable materials, such as AlCu or Au, and anyother suitable processes of formation, such as CVD or PVD, may be usedto form the first one of the series of conductive layers 133. Once theconductive material has been formed, the photoresist may be removedthrough a suitable removal process such as ashing. Additionally, afterthe removal of the photoresist, those portions of the seed layer thatwere covered by the photoresist may be removed through, for example, asuitable etch process using the conductive material as a mask.

Once the first one of the series of conductive layers 133 has beenformed, a second one of the series of dielectric layers 135 and a secondone of the series of conductive layers 133 may be formed by repeatingsteps similar to the first one of the series of dielectric layers 135and the first one of the series of conductive layers 133. These stepsmay be repeated as desired in order to electrically connect each of theseries of conductive layers 133 to an underlying one of the series ofconductive layers 133, and may be repeated as often as desired until anuppermost one of the series of conductive layers 133 and an uppermostone of the series of dielectric layers 131 has been formed. In anembodiment the deposition and patterning of the series of conductivelayers 133 and the series of dielectric layers 135 may be continueduntil the first redistribution layers 107 have a desired number oflayers, such as two layers, although any suitable number of individuallayers may be utilized.

Once the first redistribution layers 107 have been formed over thecarrier substrate 101, the first TSVs 109 are formed in electricalconnection with the first redistribution layers 107. In an embodimentthe first TSVs 109 may be formed by initially forming a seed layer (notseparately illustrated in FIG. 1A). In an embodiment the seed layer is athin layer of a conductive material that aids in the formation of athicker layer during subsequent processing steps. The seed layer maycomprise a layer of titanium about 1,000 Å thick followed by a layer ofcopper about 5,000 Å thick. The seed layer may be created usingprocesses such as sputtering, evaporation, or PECVD processes, dependingupon the desired materials. The seed layer may be formed to have athickness of between about 0.3 μm and about 1 μm, such as about 0.5 μm.

Once the seed layer has been formed, a photoresist (also not illustratedin FIG. 1A) is placed over the seed layer. In an embodiment thephotoresist may be placed on the seed layer using, e.g., a spin coatingtechnique to a height of between about 50 μm and about 250 μm, such asabout 120 μm. Once in place, the photoresist may then be patterned byexposing the photoresist to a patterned energy source (e.g., a patternedlight source) so as to induce a chemical reaction, thereby inducing aphysical change in those portions of the photoresist exposed to thepatterned light source. A developer is then applied to the exposedphotoresist to take advantage of the physical changes and selectivelyremove either the exposed portion of the photoresist or the unexposedportion of the photoresist, depending upon the desired pattern. In anembodiment the pattern formed into the photoresist is a pattern for thefirst TSVs 109. The first TSVs 109 are formed in such a placement as tobe located on different sides of subsequently attached devices such asthe fingerprint sensor 104. However, any suitable arrangement for thepattern of first TSVs 109 may be utilized.

In an embodiment the first TSVs 109 are formed within the photoresistfrom one or more conductive materials, such as copper, tungsten, otherconductive metals, or the like, and may be formed, for example, byelectroplating, electroless plating, or the like. For example, anelectroplating process is used wherein the seed layer and thephotoresist are submerged or immersed in an electroplating solution. Theseed layer surface is electrically connected to the negative side of anexternal DC power supply such that the seed layer functions as thecathode in the electroplating process. A solid conductive anode, such asa copper anode, is also immersed in the solution and is attached to thepositive side of the power supply. The atoms from the anode aredissolved into the solution, from which the cathode, e.g., the seedlayer, acquires the dissolved atoms, thereby plating the exposedconductive areas of the seed layer within the opening of thephotoresist.

Once the first TSVs 109 have been formed using the photoresist and theseed layer, the photoresist may be removed using a suitable removalprocess. In an embodiment, a plasma ashing process may be used to removethe photoresist, whereby the temperature of the photoresist may beincreased until the photoresist experiences a thermal decomposition andmay be removed. However, any other suitable process, such as a wetstrip, may be utilized. The removal of the photoresist may expose theunderlying portions of the seed layer.

Once exposed a removal of the exposed portions of the seed layer may beperformed. In an embodiment the exposed portions of the seed layer(e.g., those portions that are not covered by the first TSVs 109) may beremoved by, for example, a wet or dry etching process. For example, in adry etching process reactants may be directed towards the seed layerusing the first TSVs 109 as masks. In another embodiment, etchants maybe sprayed or otherwise put into contact with the seed layer in order toremove the exposed portions of the seed layer. After the exposed portionof the seed layer has been etched away, a portion of the firstredistribution layers 107 is exposed between the first TSVs 109.

Once the first TSVs 109 have been formed, the fingerprint sensor 104 maybe placed on the first redistribution layer 107. In an embodiment thefingerprint sensor 104 comprises a semiconductor substrate 111 with aface side 113 and a back side 115, and an array of electrodes 120located adjacent to the face side 113. In an embodiment thesemiconductor substrate 111 may comprise bulk silicon, doped or undoped,or an active layer of a silicon-on-insulator (SOI) substrate. Generally,an SOI substrate comprises a layer of a semiconductor material such assilicon, germanium, silicon germanium, SOI, silicon germanium oninsulator (SGOI), or combinations thereof. Other substrates that may beused include multi-layered substrates, gradient substrates, or hybridorientation substrates.

Additionally, while not separately illustrated in FIG. 1A, thefingerprint sensor 104 may also comprise active devices andmetallization layers in order to control and receive the input ofsignals from the array of electrodes 120 or else otherwise control thefunctionality and eventual output of the fingerprint sensor 104. In anembodiment the active devices for the fingerprint sensor 104 comprise awide variety of active devices and passive devices such as capacitors,resistors, inductors and the like that may be used to generate thedesired structural and functional requirements of the design for thefingerprint sensor 104. The active devices may be formed using anysuitable methods either within or else on the semiconductor substrate111.

The metallization layers are formed over the semiconductor substrate 111and the active devices of the fingerprint sensor 104 and are designed toconnect the various active devices to form functional circuitry. In anembodiment the metallization layers are formed of alternating layers ofdielectric and conductive material and may be formed through anysuitable process (such as deposition, damascene, dual damascene, etc.).In an embodiment there may be four layers of metallization separatedfrom the second semiconductor substrate by at least one interlayerdielectric layer (ILD), but the precise number of metallization layersis dependent upon the design of the fingerprint sensor 104.

The array of electrodes 120 is electrically connected to themetallization layers of the fingerprint sensor 104 and is used tomeasure the difference in capacitance between different areas of anoverlying finger in order to measure the fingerprint. In an embodimentthe array of electrodes 120 comprises a conductive material such asaluminum or copper, and is formed using, e.g., a deposition andpatterning process whereby a blanket layer of conductive material isdeposited using a process such as CVD, PVD, ALD, or the like, and theblanket layer of material is then patterned using a photolithographicmasking and etching process. However, any suitable material or method ofmanufacture may be utilized to form the array of electrodes 120.

Additionally, while the formation of the array of electrodes 120 hasbeen described using a blanket deposition followed by a subsequentpatterning and protection, this process is merely intended to beillustrative and is not intended to be limiting. Rather, any suitableprocess of manufacturing the array of electrodes 120, such as using adamascene or dual damascene process, may also be used. All suchprocesses are fully intended to be included within the scope of theembodiments.

Contact pads 119 are formed to provide an electrical connection to asubsequently formed second redistribution layer 121 (not illustrated inFIG. 1A but illustrated and described below with respect to FIG. 1B). Inan embodiment the contact pads 119 are formed of a conductive materialsuch as aluminum, although other suitable materials, such as copper,tungsten, or the like, may be utilized. The contact pads 119 may beformed using a process such as CVD or PVD, although other suitablematerials and methods may be utilized. Once the material for the contactpads 119 has been deposited, the material may be shaped into the contactpads 119 using, e.g., a photolithographic masking and etching process.

Once the contact pads 119 have been formed, a first protective layer 122may be placed and patterned. In an embodiment the first protective layer122 may be a protective material such as polybenzoxazole (PBO) orpolyimide (PI), silicon oxide, silicon nitride, silicon oxynitride,benzocyclobutene (BCB), or any other suitable protective material. Thefirst protective layer 122 may be formed using a method such as aspin-on process, a deposition process (e.g., chemical vapor deposition),or other suitable process based upon the chosen material, and may beformed to a thickness of between about 1 μm and about 100 μm, such asabout 20 μm.

Once formed, the first protective layer 122 is patterned to formopenings and expose the contact pads 119. In an embodiment the firstprotective layer 122 may be patterned using, e.g., a photolithographicmasking and etching process. In such a process, a photoresist (notindividually illustrated in FIG. 1B) is applied to the first protectivelayer 122 and then exposed to a patterned light source. The light sourcewill impinge upon the photoresist and induce a change in a property ofthe photoresist, which is then utilized to selectively remove either theexposed portion or the unexposed portion and expose the first protectivelayer 122. The photoresist is then utilized as a mask during, e.g., anetching process which removes portions of the first protective layer 122to expose the contact pads 119. Once the first protective layer 122 hasbeen patterned, the photoresist may be removed using, e.g., an ashingprocess.

In another embodiment the first protective layer 122 may be thinned inorder to expose the contact pads 119. In this embodiment a planarizationprocess such as a chemical mechanical polishing process, wherebychemicals and abrasives are applied to the first protective layer 122while a polishing pad grinds away material, may be utilized to removethe material of the first protective layer 122 from over the contactpads 119, thereby exposing the contact pads 119 while also planarizingthe first protective layer 122 with the contact pads 119. Any suitablemethod of forming the contact pads 119 and the first protective layer122 may be used.

The fingerprint sensor 104 is placed on the first redistribution layer107 between the first TSVs 109 using, e.g., a second adhesive layer 112.In an embodiment the second adhesive layer 112 may be a similar materialand applied in a similar fashion as the adhesive layer 103, although anysuitable material may be used. The fingerprint sensor 104 is placed faceup such that the face side 113 is facing away from the carrier substrate101. Additionally, the contact pads 119 are connected to the array ofelectrodes 120 and the metallization layers of the fingerprint sensor104 on the face side 113 of the fingerprint sensor 104.

FIG. 1B illustrates an encapsulation of the fingerprint sensor 104 andthe first TSVs 109 with an encapsulant 125. In an embodiment theencapsulant 125 may be a molding compound and may be placed using amolding device (not illustrated in FIG. 1B). For example, thefingerprint sensor 104 may be placed within a cavity of the moldingdevice, and the cavity may be hermetically sealed. The encapsulant 125may be placed within the cavity either before the cavity is hermeticallysealed or else may be injected into the cavity through an injectionport. In an embodiment the encapsulant 125 may be a molding compoundresin such as polyimide, PPS, PEEK, PES, a heat resistant crystal resin,combinations of these, or the like.

Once the encapsulant 125 has been placed into the cavity such that theencapsulant 125 encapsulates the region around the fingerprint sensor104 and the first TSVs 109, the encapsulant 125 may be cured in order toharden the encapsulant 125 for optimum protection. While the exactcuring process is dependent at least in part on the particular materialchosen for the encapsulant 125, in an embodiment in which moldingcompound is chosen as the encapsulant 125, the curing could occurthrough a process such as heating the encapsulant 125 to between about100° C. and about 130° C., such as about 125° C. for about 60 sec toabout 3000 sec, such as about 600 sec. Additionally, initiators and/orcatalysts may be included within the encapsulant 125 to better controlthe curing process.

However, as one having ordinary skill in the art will recognize, thecuring process described above is merely an exemplary process and is notmeant to limit the current embodiments. Other curing processes, such asirradiation or even allowing the encapsulant 125 to harden at ambienttemperature, may be used. Any suitable curing process may be used, andall such processes are fully intended to be included within the scope ofthe embodiments discussed herein.

FIG. 1B additionally illustrates a thinning of the encapsulant 125 inorder to expose the contact pads 119 of the fingerprint sensor 104. Inan embodiment the thinning may be performed, e.g., using a mechanicalgrinding or chemical mechanical polishing (CMP) process whereby chemicaletchants and abrasives are utilized to react and grind away theencapsulant 125. The encapsulant 125 may be thinned until the contactpads 119 have been exposed.

However, while the CMP process described above is presented as oneillustrative embodiment, it is not intended to be limiting to theembodiments. Any other suitable removal process may be used toencapsulate the fingerprint sensor 104 while exposing the contact pads119. For example, a chemical etch or a series of chemical etches may beutilized, or an encapsulation process that does not cover the contactpads 119 may be utilized. These processes and any other suitable processmay be utilized to apply the encapsulant 125, and all such processes arefully intended to be included within the scope of the embodiments.

FIG. 1B also illustrates a formation of a second redistribution layer121 in order to electrically interconnect the first TSVs 109 with thecontact pads 119 of the fingerprint sensor 104. In an embodiment thesecond redistribution layer 121 may be similar to the firstredistribution layer 107 described above with respect to FIG. 1A. In aparticular embodiment, there may be a single one of the series ofconductive layers 133 sandwiched between two of the series of dielectriclayers 135. However, any suitable combination of conductive layers anddielectric layers may be utilized to interconnect the contact pads 119of the fingerprint sensor 104 with the first TSVs 109.

Once the second redistribution layer 121 has been formed, a sensorsurface material 123 may be attached to the second redistribution layer121 using, e.g., an interface layer 136, such as a glue layer or a colorfilm layer. In an embodiment the sensor surface material 123 may beattached by initially applying the interface layer 136 to the secondredistribution layer 121 and then applying the sensor surface material123 to the interface layer 136. The interface layer 136 may be similarto the adhesive layer 103 described above with respect to FIG. 1A,although any suitable material may be used.

In an embodiment the sensor surface material 123 is a material such assapphire or glass that allows for the measurement of capacitive changesbetween the fingerprint sensor 104 and an overlying finger to determinecontours of a fingerprint on the finger. In an embodiment the sensorsurface material 123 may be placed using a physical placing process.Additionally, the sensor surface material 123 may have a first thicknessT₁ of between about 50 μm and about 1000 μm, such as about 100 μm.However, any suitable material and thickness may be utilized.

In another embodiment in which the interface layer 136 is a color filmlayer, the sensor surface material may be omitted. For example, in aparticular embodiment the interface layer 136 may be placed over thesecond redistribution layer 121 by itself, without then placing thesensor surface material onto the interface layer 136. Any suitablecombination of materials may be utilized.

FIG. 1C illustrates a debonding of the carrier substrate 101 and apatterning of the polymer layer 105 in order to expose the underbumpmetallization layers 137. In an embodiment the carrier substrate 101 maybe debonded by initially bonding the sensor surface material 123 to,e.g., a ring structure 152. The ring structure 152 may be a metal ringintended to provide support and stability for the structure during andafter the debonding process. In an embodiment the sensor surfacematerial 123 may be attached to the ring structure 152 using, e.g., aultraviolet tape 154, although any other suitable adhesive or attachmentmay be used.

Once attached, the carrier substrate 101 may be debonded from thestructure using, e.g., a thermal process to alter the adhesiveproperties of the adhesive layer 103. In a particular embodiment anenergy source such as an ultraviolet (UV) laser, a carbon dioxide (CO₂)laser, or an infrared (IR) laser, is utilized to irradiate and heat theadhesive layer 103 until the adhesive layer 103 loses at least some ofits adhesive properties. Once performed, the carrier substrate 101 andthe adhesive layer 103 may be physically separated and removed from thestructure comprising the fingerprint sensor 104 and the sensor surfacematerial 123.

Once debonded, the polymer layer 105 is patterned in order to expose theunderlying underbump metallization layers 137. In an embodiment thepolymer layer 105 may be patterned using, e.g., a laser drilling method.In such a method a protective layer, such as a light-to-heat conversion(LTHC) layer or a hogomax layer (not separately illustrated in FIG. 1C)is first deposited over the polymer layer 105. Once protected, a laseris directed towards those portions of the polymer layer 105 which aredesired to be removed in order to expose the underlying underbumpmetallization layers 137. During the laser drilling process the drillenergy may be in a range from 0.1 mJ to about 30 mJ, and a drill angleof about 0 degree (perpendicular to the polymer layer 105) to about 85degrees to normal of the polymer layer 105. In an embodiment thepatterning may be formed to form openings over the underbumpmetallization layers 137 to have a width of between about 100 μm andabout 300 μm, such as about 200 μm.

In another embodiment, the polymer layer 105 may be patterned byinitially applying a photoresist (not individually illustrated in FIG.1C) to the polymer layer 105 and then exposing the photoresist to apatterned energy source (e.g., a patterned light source) so as to inducea chemical reaction, thereby inducing a physical change in thoseportions of the photoresist exposed to the patterned light source. Adeveloper is then applied to the exposed photoresist to take advantageof the physical changes and selectively remove either the exposedportion of the photoresist or the unexposed portion of the photoresist,depending upon the desired pattern, and the underlying exposed portionof the polymer layer 105 are removed with, e.g., a dry etch process.However, any other suitable method for patterning the polymer layer 105may be utilized.

FIG. 1D illustrates that, once the polymer layer 105 has been patternedto expose the underbump metallization layers 137, a high voltage chip141 may be bonded to the underbump metallization layers 137 through thepolymer layer 105 to form a first sensor package 149. In an embodimentthe high voltage chip 141 is designed and connected in order to supply ahigh voltage, such as between about 5 V and about 50 V, such as about 33V, to the fingerprint sensor 104 in order to amplify the sensor'ssensitivity. For example, by integrating the high voltage chip 141 withthe fingerprint sensor 104 such that a high voltage can be supplied tothe fingerprint sensor 104, the sensitivity of the fingerprint sensor104 may be increased ten times by raising the input voltage to 33 Vfrom, e.g., 3.3 V.

In an embodiment the high voltage chip 141 may comprise a secondsemiconductor substrate (not separately illustrated), active devices(not separately illustrated), metallization layers (not separatelyillustrated) utilized to interconnect the active devices of the highvoltage chip 141, and first external connections 143 in order tointerconnect the high voltage chip 141 to the fingerprint sensor 104.The second semiconductor substrate may comprise bulk silicon, doped orundoped, or an active layer of a silicon-on-insulator (SOI) substrate.Generally, an SOI substrate comprises a layer of a semiconductormaterial such as silicon, germanium, silicon germanium, SOI, silicongermanium on insulator (SGOI), or combinations thereof. Other substratesthat may be used include multi-layered substrates, gradient substrates,or hybrid orientation substrates.

The active devices for the high voltage chip 141 comprise a wide varietyof active devices and passive devices such as capacitors, resistors,inductors and the like that may be used to generate the desiredstructural and functional requirements of the design for the highvoltage chip 141. The active devices may be formed using any suitablemethods either within or else on the second semiconductor substrate.

The metallization layers for the high voltage chip 141 are formed overthe second semiconductor substrate and the active devices of the highvoltage chip 141 and are designed to connect the various active devicesto form functional circuitry. In an embodiment the metallization layersare formed of alternating layers of dielectric and conductive materialand may be formed through any suitable process (such as deposition,damascene, dual damascene, etc.). In an embodiment there may be fourlayers of metallization separated from the second semiconductorsubstrate by at least one interlayer dielectric layer (ILD), but theprecise number of metallization layers is dependent upon the design ofthe high voltage chip 141.

The first external connections 143 may be formed to interconnect thehigh voltage chip 141 to the fingerprint sensor 104 and may be, forexample, contact bumps, although any suitable connection may beutilized. In an embodiment in which the first external connections 143are contact bumps, the first external connections 143 may comprise amaterial such as tin, or other suitable materials, such as silver,lead-free tin, or copper. In an embodiment in which the first externalconnections 143 are tin solder bumps, the first external connections 143may be formed by initially forming a layer of tin through such commonlyused methods such as evaporation, electroplating, printing, soldertransfer, ball placement, etc, to a thickness of, e.g., between about 30μm and about 100 μm. Once a layer of tin has been formed on thestructure, a reflow may be performed in order to shape the material intothe desired bump shape.

The high voltage chip 141 may be formed to have a first width W₁ ofbetween about 1 mm and about 5 mm, such as about 1.5 mm, and may also beformed to have a second thickness T₂ of between about 70 μm and about150 μm, such as about 100 μm. Additionally, while not shown in FIG. 1Dbecause it would extend into and out of the figure, the high voltagechip 141 may also be formed to have a first length of between about 1 mmand about 5 mm, such as about 2 mm. However, any suitable dimensions maybe utilized for the high voltage chip 141.

The high voltage chip 141 may be connected to the underbumpmetallization layers 137, for example, by initially applying a solderpaste to the exposed underbump metallization layers 137 and then flipchip bonding the high voltage chip 141 to the underbump metallizationlayers 137. In an embodiment the high voltage chip 141 may be bonded bysequentially dipping the first external connections 143 of the highvoltage chip 141 into flux, and then using a pick-and-place tool inorder to physically align the first external connections 143 of the highvoltage chip 141 with individual ones of the underbump metallizationlayers 137. In an embodiment in which the first external connections 143are solder balls, once the high voltage chip 141 has been placed areflow process may be performed in order to physically bond the highvoltage chip 141 with the underlying underbump metallization layers 137and a flux clean may be performed. However, any other suitable connectoror connection process may be utilized, such as metal-to-metal bonding orthe like.

Once the high voltage chip 141 has been bonded to the underbumpmetallization layers 137, an underfill material 147 may be placedbetween the high voltage chip 141 and the fingerprint sensor 104 inorder to help protect and isolate the devices. In an embodiment theunderfill material 147 is a protective material used to cushion andsupport the high voltage chip 141 from operational and environmentaldegradation, such as stresses caused by the generation of heat duringoperation. The underfill material 147 may comprise, for example, aliquid epoxy or other protective material, and then cured to harden andmay be dispensed by, e.g., injection.

Additionally, after the first polymer layer 105 has been patterned,second external connections 139 may be utilized to provide an externalconnection point for electrical connection to the first redistributionlayer 107 and may be, for example, a contact bump as part of a ball gridarray (BGA), although any suitable connection may be utilized. In anembodiment in which the second external connections 139 are contactbumps, the second external connections 139 may comprise a material suchas tin, or other suitable materials, such as silver, lead-free tin, orcopper. In an embodiment in which the second external connections 139are tin solder bumps, the second external connections 139 may be formedby initially forming a layer of tin through such commonly used methodssuch as evaporation, electroplating, printing, solder transfer, ballplacement, etc, to a thickness of, e.g., about 250 μm. Once a layer oftin has been formed on the structure, a reflow may be performed in orderto shape the material into the desired bump shape.

FIG. 1E illustrates a bonding of the structure to a substrate 150. In anembodiment the substrate 150 may be, e.g., a printed circuit board thatworks to interconnect various electrical components to each other inorder to provide a desired functionality for a user. Alternatively, thesubstrate 150 may be a flexible substrate or comprise multipleconductive layers (not individually illustrated) which may be etchedinto traces of various widths and lengths and connected throughinter-layer vias. Together, the lines and vias may form an electricalnetwork to route DC power, ground, and signals from one side of thesubstrate 150 to the other. Those of skill in the art will recognizethat the substrate 150 may be fabricated from an organic (laminate)material such as bismaleimide-triazine (BT), a polymer-based materialsuch as liquid-crystal polymer (LCP), a ceramic material such aslow-temperature co-fired ceramic (LTCC), a silicon or glass interposer,or the like. Those of skill in the art will also recognize that theconductive layers and vias may be formed from any suitable conductivematerial, such as copper, aluminum, silver, gold, other metals, alloys,combination thereof, and/or the like, and formed by any suitabletechnique, such as electro-chemical plating (ECP), electroless plating,other deposition methods such as sputtering, printing, and chemicalvapor deposition (CVD) methods, or the like. The substrate 150 may beformed or acquired with a third thickness T₃ of between about 100 μm andabout 1000 μm, such as about 200 μm, although any suitable thickness maybe utilized.

In some embodiments, the substrate 150 may also include electricalelements, such as resistors, capacitors, signal distribution circuitry,combinations of these, or the like. These electrical elements may beactive, passive, or a combination thereof. In other embodiments, thesubstrate 150 is free from both active and passive electrical elementstherein. All such combinations are fully intended to be included withinthe scope of the embodiments.

Additionally, in order to accommodate the presence of the high voltagechip 141, the substrate 150 may be formed with, or have formed therein,a first opening 151. In an embodiment the first opening 151 is sized inorder to accommodate the high voltage chip 141 and, as such, thedimensions of the first opening 151 are dependent at least in part uponthe dimensions of the high voltage chip 141. However, in an embodimentin which the high voltage chip 141 has the first width W₁, the firstlength, and the second thickness T₂, the first opening 151 may be formedto have a second width W₂ of between about 2 mm and about 6 mm, such asabout 2.5 mm. Additionally, the first opening 151 may have a secondlength (not separately illustrated in FIG. 1E as the second length willextend into and out of the figure) of between about 2 mm and about 6 mm,such as about 3.5 mm. However, any suitable dimensions that accommodatethe high voltage chip 141 may be utilized.

Additionally, in some embodiments, and as illustrated in FIG. 1E, thefirst opening 151 will extend all of the way through the substrate 150.As such, the first opening 151 will have the third thickness T₃ of thesubstrate 150, such as by being between about 0.1 mm and about 1 mm,such as about 0.2 mm. However, any suitable dimension may be used.

In another embodiment (illustrated in FIG. 1E by the dashed lines), thefirst opening 151 may be formed to extend partially, but not fully,through the substrate 150. In this embodiment, the first opening 151 maybe formed to extend into the substrate 150 a first depth D₁ of betweenabout 50 μm and about 500 μm, such as about 100 μm. However, anysuitable depth may be utilized to accommodate the high voltage chip 141.

The substrate 150 may further comprise second contact pads 153 thatallow for electrical connection with the second external connections139. In an embodiment the second contact pads 153 may be formed fromsimilar materials and using similar processes as the contact pads 119described above with respect to FIG. 1A. For example, the second contactpads 153 may be aluminum contact pads formed using a process such as CVDor PVD. However, any suitable material or method of manufacturing thesecond contact pads 153 may be used.

In order to bond the second contact pads 153 with the second externalconnections 139, the second contact pads 153 and the second externalconnections 139 are first aligned with each other. For example, in anembodiment the second external connections 139 may be aligned and placedinto physical contact with the second contact pads 153. Once in placeand aligned, the second external connections 139 may be reflowed inorder to physically and electrically bond the second externalconnections 139 to the substrate 150.

By attaching the fingerprint sensor 104 to the substrate 150 such thatthe high voltage chip 141 is located within the first opening 151, theoverall height of the structure may be reduced. For example, in anembodiment the overall height of the substrate 150 along with theattached fingerprint sensor 104 may be a first height H₁ of betweenabout 0.4 mm and about 1.5 mm, such as about 0.5 mm. However, anysuitable height may be utilized.

FIG. 1F illustrates another embodiment in which the high voltage chip141, instead of being centered below the fingerprint sensor 104, may belocated as desired with respect to the fingerprint sensor 104. Forexample, in the embodiment illustrated in FIG. 1F, the high voltage chip141 may be located a second distance D₂ from a first side of thefingerprint sensor 104 (in this top down view) of between about 80 μmand about 4000 μm, such as about 1000 μm, and also located a thirddistance D₃ from a second side of the fingerprint sensor 104 of betweenabout 80 μm and about 4000 μm, such as about 1500 μm. However, anysuitable placement of the high voltage chip 141 relative to thefingerprint sensor 104 may be utilized.

By forming the first sensor package 149 as described above, not only canthe sensitivity of the fingerprint sensor 104 be enhanced by minimizingthe sensing gap between the array of electrodes 120 and the finger, buta fan-in with through vias is used to integrate the high voltage chip141 and increase charge (Q=C×V). Such an increase allows for an increasein the sensitivity of the sensor.

FIG. 2A illustrates another embodiment that illustrates a second sensorpackage 200 that uses through substrate vias 201 that extend through thesemiconductor substrate 111 in order to connect the array of electrodes120 and a third redistribution layer 203. In this embodiment, however,the through substrate vias 201 are utilized to electrically connect thearray of electrodes 120 and the metallization layers which are locatedon the face side 113 of the fingerprint sensor 104 to the back side 115of the fingerprint sensor 104. The through substrate vias 201 may beformed by initially applying and developing a suitable photoresist tothe semiconductor substrate 111 prior to the formation of themetallization layers, and then etching the semiconductor substrate 111to generate TSV openings. The openings for the through substrate vias201 at this stage may be formed so as to extend into the semiconductorsubstrate 111 to a depth at least greater than the eventual desiredheight of the finished semiconductor substrate 111.

Once the openings for the through substrate vias 201 have been formed,the openings for the through substrate vias 201 may be filled with,e.g., a barrier layer and a conductive material. The barrier layer maycomprise a conductive material such as titanium nitride, although othermaterials, such as tantalum nitride, titanium, a dielectric, or the likemay be utilized. The barrier layer may be formed using a CVD process,such as PECVD. However, other processes, such as sputtering or metalorganic chemical vapor deposition (MOCVD), may be used. The barrierlayer may be formed so as to contour to the underlying shape of theopening for the through substrate vias 201.

The conductive material may comprise copper, although other suitablematerials such as aluminum, alloys, doped polysilicon, combinationsthereof, and the like, may be utilized. The conductive material may beformed by depositing a seed layer and then electroplating copper ontothe seed layer, filling and overfilling the openings for the throughsubstrate vias 201. Once the openings for the through substrate vias 201have been filled, excess barrier layer and excess conductive materialoutside of the openings for the through substrate vias 201 may beremoved through a grinding process such as chemical mechanical polishing(CMP), although any suitable removal process may be used.

Once the conductive material is within the openings for the throughsubstrate vias 201, a thinning of the semiconductor substrate 111 may beperformed in order to expose the openings for the through substrate vias201 and form the through substrate vias 201 from the conductive materialthat extends through the semiconductor substrate 111. In an embodiment,the thinning of the semiconductor substrate 111 may be performed by aplanarization process such as CMP or etching, leaving the throughsubstrate vias 201 planar with the semiconductor substrate 111.

However, as one of ordinary skill in the art will recognize, the abovedescribed process for forming the through substrate vias 201 is merelyone method of forming the through substrate vias 201, and other methodsare also fully intended to be included within the scope of theembodiments. For example, forming the openings for the through substratevias 201, filling the openings for the through substrate vias 201 with adielectric material, thinning the semiconductor substrate 111 to exposethe dielectric material, removing the dielectric material, and fillingthe openings for the through substrate vias 201 with a conductor mayalso be used. This and all other suitable methods for forming thethrough substrate vias 201 into the semiconductor substrate 111 arefully intended to be included within the scope of the embodiments.

Once the through substrate vias 201 have been formed (and the activedevices and metallization layers have been also been completed asdesired), the third redistribution layer 203 may be formed in electricalconnection with the through substrate vias 201 in order to provideinterconnectivity between the through substrate vias 201 and, e.g., thehigh voltage chip 141 and the second external connections 139. In anembodiment the third redistribution layer 203 may be formed with similarmaterials and using similar processes as described above with respect tothe first redistribution layer 107. For example, the thirdredistribution layer 203 may be formed of multiple layers of conductiveand dielectric materials formed using deposition and photolithographicmasking and etching processes. However, any suitable materials ormethods of formation may be utilized to form the third redistributionlayer 203.

Once the third redistribution layer 203 has been formed, the highvoltage chip 141 may be bonded to the third redistribution layer 203,and the second external connections 139 may be placed to be inelectrical connection with the third redistribution layer 203. In anembodiment the high voltage chip 141 and the second external connections139 may be formed or placed as described above with respect to FIG. 1D.For example, the high voltage chip 141 may be bonded to the thirdredistribution layer 203 and the first external connections 129 may beplaced and reflowed.

Additionally, before or after the high voltage chip 141 and the firstexternal connections 129 have been formed or placed, the sensor surfacematerial 123 may be attached to the fingerprint sensor 104 using, e.g.,the interface layer 136. In an embodiment the sensor surface material123 may be attached with the interface layer 136 as described above withrespect to FIG. 1B. For example, the interface layer 136 may bephysically contacted to both the sensor surface material 123 and thefingerprint sensor 104. However, any suitable method of attaching thesensor surface material 123 may be utilized.

FIG. 2B illustrates an attachment of the substrate 150 to the secondsensor package 200. In an embodiment the second sensor package 200 isbonded to the substrate 150 as described above with respect to FIG. 1E.For example, the second external connections 139 are aligned with thesecond contact pads 153, and a reflow process is performed toelectrically and physically bond the second external connections 139with the second contact pads 153. However, any suitable method ofbonding the second sensor package 200 with the substrate 150 may beutilized.

Additionally, during the bonding process the high voltage chip 141 isaligned with and inserted within the first opening 151 that is locatedwithin (or through) the substrate 150. In an embodiment the firstopening 151 is formed or located so as to accept the high voltage chip141 and allowing the overall height of the combined substrate 150 andsecond sensor package 200 to be reduced. For example, the overall heightof the structure in this embodiment may be reduced to a second height H₂of between about 370 μm and about 1500 μm, such as about 400 μm.However, any suitable height may be utilized.

By forming the third redistribution layer 203 along with the throughsubstrate vias 201 as described, the through substrate vias 201 and thethird redistribution layer 203 may be used to output a redistributedsignal from the fingerprint sensor 104. Additionally, with the inclusionof the substrate 150 and the first opening 151 within the substrate 150,a flexible SMT process with the high voltage chip 141 inside the firstopening 151 may be achieved.

FIGS. 3A-3B illustrate another embodiment in which the through substratevias 201 are formed in electrical connection with the second externalconnections 139 and the high voltage chip 141 without the use of thethird redistribution layer 203 to form a third sensor package 300. Inthis embodiment, instead of forming the third redistribution layer 203on the back side 115 of the semiconductor substrate 111, third contactpads 301 are formed directly over and in physical and/or electricalconnection with the through substrate vias 201. In an embodiment thethird contact pads 301 may be formed using similar materials andprocesses as described above with respect to the contact pads 119. Forexample, the third contact pads 301 may be formed from aluminum using adeposition and patterning process. However, any suitable process forforming the third contact pads 301 may be utilized.

Once the third contact pads 301 have been formed, a second protectivelayer 303 may be formed over the third contact pads 301. In anembodiment the second protective layer 303 may be a protective materialsuch as polybenzoxazole (PBO) or polyimide (PI), silicon oxide, siliconnitride, silicon oxynitride, benzocyclobutene (BCB), or any othersuitable protective material. The second protective layer 303 may beformed using a method such as a spin-on process, a deposition process(e.g., chemical vapor deposition), or other suitable process based uponthe chosen material, and may be formed to a thickness of between about 1μm and about 100 μm, such as about 20 μm. Once in place, the secondprotective layer 303 may be patterned in order to expose the thirdcontact pads 301.

Once the third contact pads 301 have been formed, the sensor surfacematerial 123 may be placed over the fingerprint sensor 104, the highvoltage chip 141 may be bonded to the third contact pads 301, and thesecond external connections 139 may be placed to be in electricalconnection with the third contact pads 301. In an embodiment the sensorsurface material 123, the high voltage chip 141 and the second externalconnections 139 may be formed or placed as described above with respectto FIGS. 1B-1D. For example, the sensor surface material 123 may beadhered with the second glue layer 126, the high voltage chip 141 may bebonded to the third contact pads 301 and the first external connections129 may be placed and reflowed.

FIG. 3B illustrates an attachment of the substrate 150 to the thirdsensor package 300. In an embodiment the third sensor package 300 isbonded to the substrate 150 as described above with respect to FIG. 1E.For example, the second external connections 139 are aligned with thesecond contact pads 153, and a reflow process is performed toelectrically and physically bond the second external connections 139with the second contact pads 153. However, any suitable method ofbonding the third sensor package 300 with the substrate 150 may beutilized.

Additionally, during the bonding process the high voltage chip 141 isaligned with and inserted within the first opening 151 that is locatedwithin (or through) the substrate 150. In an embodiment the firstopening 151 is formed or located so as to accept the high voltage chip141 and allowing the overall height of the combined substrate 150 andthird sensor package 300 to be reduced.

By bonding the high voltage chip 141 directly over the through substratevias 201, the processing steps that are used to form the thirdredistribution layer 203 may be avoided, allowing for a simpler and lesscomplicated manufacturing process. Additionally, by not manufacturingthe third redistribution layer 203, the overall height of the structurewithout the third redistribution layer 203 may be reduced. For example,in an embodiment the overall structure may have a third height H₃ ofbetween about 360 μm and about 1500 μm, such as about 390 μm. However,any suitable height may be utilized.

FIG. 4 illustrates an embodiment in which the substrate 150 and thefirst sensor package 149 are incorporated into, e.g., a semiconductordevice structure 400 with the first sensor package 149 located at afirst side of the semiconductor device structure 400 and a displaydevice 409 located at a second side opposite the first side. In anembodiment the semiconductor device structure 400 includes a multi-chippackage system (MCPS) 413 with the fingerprint sensor 104 attached toTHE MCPS 413 through the substrate 150, with the substrate 150 beingbonded to the MCPS 413 through, e.g., connectors 417, such as solderbumps, although any suitable connector may be utilized.

In some embodiments, other electrical components 415 a and 415 b inadditional to the MCPS 413 are also attached to the substrate 150 by theconnectors 417. The electric components 415 a and 415 b may be similarto or different from each other. As an example, the electrical component415 a may be a semiconductor die or a semiconductor package, and theelectric component 415 b may be a discrete electrical component, e.g., apassive or active device such as a capacitor, inductor, resistor,transistor, diode, or the like. One skilled in the art will appreciatethat FIG. 4 is just an illustration, as different numbers of the MCPS413 and the electrical components 415 a/415 b could be used inconjunction with the fingerprint sensor 104 without departing from thespirit of the current disclosure.

As illustrated in FIG. 4, a battery 411 is electrically coupled to thesubstrate 150 by a cable 419, with the MCPS 413 disposed between thebattery 411 and the substrate 150. In some embodiments, the cable 419 isa flexible cable, such as a flexible printed circuit (FPC) cable. Thedisplay device 409, such as an LCD display device, is disposed next tobattery 411, with battery 411 being disposed between the MCPS 413 andthe display device 409. The display device 409 is electrically coupledto the substrate 150 by a cable 421, such as an FPC cable, in someembodiments.

Additionally, the semiconductor device structure 400 has a housing 401,in accordance with some embodiments. In some embodiments, semiconductordevice structure 400 comprises a wearable device, such as a smart watch,a fitness device, or a health monitoring device.

By attaching the first sensor package 149 to the substrate 150 asdescribed, and incorporating the structure into the semiconductor devicestructure 400, the thickness of the individual components may bereduced, allowing for a larger sized battery 411 to be used. Forexample, in an embodiment the height of the battery 411 may be increasedto have a fourth height H₄ of between about 3 mm and about 7 mm, such asabout 5 mm. By increasing the size of the battery 411 without increasingthe size of the structure, a semiconductor device may run for a longerperiod of time between recharges.

FIG. 5 illustrates an alternative embodiment in which the savings insize may not be used to incorporate a larger battery, but may instead beused to reduce the overall size of the semiconductor device structure400. In this embodiment the semiconductor device structure 400 may bereduced to have an overall fifth height H₅ of between about 8 mm andabout 15 mm, such as about 10 mm. However, any suitable size may beutilized. By reducing the size, a smaller overall structure may beachieved.

Additionally, while the embodiments described in FIG. 4 and FIG. 5 aredescribed with respect to the first sensor package 149 described abovewith respect to FIGS. 1A-1F, the embodiments are not limited to thefirst sensor package 149. Rather, any suitable sensor package, such asthe second sensor package 200 or the third sensor package 300, may alsobe utilized. All suitable combinations are fully intended to be includedwithin the scope of the embodiments.

In accordance with an embodiment, a method of manufacturing afingerprint scanner comprising attaching a fingerprint sensor surfacematerial over a fingerprint sensor is provided. The fingerprint sensorcomprises a semiconductor substrate and an array of electrodes betweenthe semiconductor substrate and the fingerprint sensor surface material.A high voltage chip is attached in electrical connection with thefingerprint sensor, wherein the high voltage chip is located on anopposite side of the fingerprint sensor than the fingerprint sensorsurface material. The fingerprint sensor is attached to a substrate,wherein the high voltage chip is located within an opening of thesubstrate after the attaching the fingerprint sensor to the substrate.

In accordance with another embodiment, a method of manufacturing afingerprint scanner, the method comprising forming through vias througha fingerprint sensor substrate is provided. An array of electrodes isformed over the fingerprint sensor substrate, wherein the array ofelectrodes are in electrical connection with active devices on a firstside of the fingerprint sensor substrate, and a fingerprint sensor coveris attached over the first side of the fingerprint sensor substrate. Ahigh voltage chip is attached in electrical connection with the activedevices, wherein the high voltage chip is located on an opposite side ofthe fingerprint sensor substrate from the array of electrodes, and thehigh voltage chip is placed into an opening located within a secondsubstrate.

In accordance with yet another embodiment, a semiconductor devicecomprising a fingerprint sensor is provided. Through vias electricallyconnect a first side of the fingerprint sensor with a conductive elementlocated on a second side of the fingerprint sensor opposite the firstside. A high voltage chip is in electrical connection with the throughvias, and a substrate is in electrical connection with the through vias,wherein the high voltage chip is located within an opening of thesubstrate.

In accordance with yet another embodiment, a semiconductor deviceincludes a fingerprint sensor and a high voltage chip in electricalconnection with the fingerprint sensor. The high voltage chip has afirst surface disposed at a first distance from the fingerprint sensor.The semiconductor device further includes a substrate in electricalconnection with the fingerprint sensor. The substrate has a secondsurface disposed at a second distance from the fingerprint sensor. Thefirst distance is greater than the second distance.

In accordance with yet another embodiment, a semiconductor deviceincludes a sensor module having a first side and a second side oppositeto the first side, a first metallization layer on the first side of thesensor module, a second metallization layer on a second side of thesensor module, and a high voltage chip attached to the secondmetallization layer. The second metallization layer is interposedbetween high voltage chip and the sensor module.

In accordance with yet another embodiment, a semiconductor deviceincludes a high voltage chip electrically connected to a firstredistribution layer and a sensor chip electrically connected to thefirst redistribution layer. The first redistribution layer is interposedbetween the sensor chip and the high voltage chip. The semiconductordevice further includes a second redistribution layer electricallyconnected to the sensor chip. The sensor chip is interposed between thefirst redistribution layer and the second redistribution layer.

In accordance with yet another embodiment, a method includes attaching afingerprint sensor to a first side of a first redistribution layer. Ahigh voltage chip is attached to a second side of the firstredistribution layer. The second side of the first redistribution layeris opposite to the first side of the first redistribution layer. Asubstrate is attached to the second side of the first redistributionlayer. The high voltage chip extends into an opening of the substrate.

In accordance with yet another embodiment, a method includes forming aplurality of through vias in a fingerprint sensor substrate. Theplurality of through vias extend from a first side of the fingerprintsensor substrate to a second side of the fingerprint sensor substrate.The first side of the fingerprint sensor substrate is opposite to thesecond side of the fingerprint sensor substrate. A first redistributionlayer is formed on the first side of the fingerprint sensor substrate. Ahigh voltage chip is attached to the first redistribution layer. Thefirst redistribution layer is interposed between the high voltage chipand the fingerprint sensor substrate. A second substrate is attached tothe first redistribution layer. The first redistribution layer isinterposed between the second substrate and the fingerprint sensorsubstrate.

In accordance with yet another embodiment, a method includes forming aplurality of first through vias and a plurality of second through viasin a fingerprint sensor substrate. The plurality of first through viasand the plurality of second through vias extend from a first side of thefingerprint sensor substrate to a second side of the fingerprint sensorsubstrate. The first side of the fingerprint sensor substrate isopposite to the second side of the fingerprint sensor substrate. Anarray of electrodes is formed over the first side of the fingerprintsensor substrate. A fingerprint sensor cover is attached to the firstside of the fingerprint sensor substrate. The array of electrodes isinterposed between the fingerprint sensor substrate and fingerprintsensor cover. A high voltage chip is attached to the second side of thefingerprint sensor substrate. The high voltage chip is bonded to theplurality of first through vias. A second substrate is attached to thesecond side of the fingerprint sensor substrate. The second substrate isbonded to the plurality of second through vias.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A method comprising: attaching a fingerprintsensor to a first side of a first redistribution layer; attaching a highvoltage chip to a second side of the first redistribution layer, whereinthe second side of the first redistribution layer is opposite to thefirst side of the first redistribution layer; and attaching a substrateto the second side of the first redistribution layer, wherein the highvoltage chip extends into an opening of the substrate.
 2. The method ofclaim 1, further comprising forming a conductive column on the firstside of the first redistribution layer adjacent the fingerprint sensor.3. The method of claim 2, further comprising encapsulating thefingerprint sensor and the conductive column in an encapsulant.
 4. Themethod of claim 1, forming a second redistribution layer in electricalcontact with the fingerprint sensor, wherein the fingerprint sensor isinterposed between the first redistribution layer and the secondredistribution layer.
 5. The method of claim 4, further comprisingforming a sensor surface material layer on the second redistributionlayer, wherein the second redistribution layer is interposed between thesensor surface material layer and the fingerprint sensor.
 6. The methodof claim 1, wherein a center of the high voltage chip is spaced apartfrom a center of the fingerprint sensor in a plan view.
 7. The method ofclaim 1, wherein a width of the high voltage chip is less than a widthof the fingerprint sensor.
 8. A method comprising: forming a pluralityof through vias in a fingerprint sensor substrate, the plurality ofthrough vias extending from a first side of the fingerprint sensorsubstrate to a second side of the fingerprint sensor substrate, thefirst side of the fingerprint sensor substrate being opposite to thesecond side of the fingerprint sensor substrate; forming a firstredistribution layer on the first side of the fingerprint sensorsubstrate; attaching a high voltage chip to the first redistributionlayer, the first redistribution layer being interposed between the highvoltage chip and the fingerprint sensor substrate; and attaching asecond substrate to the first redistribution layer, the firstredistribution layer being interposed between the second substrate andthe fingerprint sensor substrate.
 9. The method of claim 8, wherein thesecond substrate has an opening, and wherein the high voltage chip isdisposed within the opening.
 10. The method of claim 8, forming an arrayof electrodes on the second side of the fingerprint sensor substrate,wherein the plurality of through vias electrically couple the array ofelectrodes to the first redistribution layer.
 11. The method of claim 8,further comprising attaching a fingerprint sensor cover to the secondside of the fingerprint sensor substrate.
 12. The method of claim 11,wherein the fingerprint sensor cover is attached to the second side ofthe fingerprint sensor substrate using a glue layer.
 13. The method ofclaim 8, wherein the high voltage chip is disposed at a corner of thefingerprint sensor substrate in a plan view.
 14. The method of claim 8,wherein a width of the high voltage chip is less than a width of thefingerprint sensor substrate.
 15. A method comprising: forming aplurality of first through vias and a plurality of second through viasin a fingerprint sensor substrate, the plurality of first through viasand the plurality of second through vias extending from a first side ofthe fingerprint sensor substrate to a second side of the fingerprintsensor substrate, the first side of the fingerprint sensor substratebeing opposite to the second side of the fingerprint sensor substrate;forming an array of electrodes over the first side of the fingerprintsensor substrate; attaching a fingerprint sensor cover to the first sideof the fingerprint sensor substrate, wherein the array of electrodes isinterposed between the fingerprint sensor substrate and fingerprintsensor cover; attaching a high voltage chip to the second side of thefingerprint sensor substrate, wherein the high voltage chip is bonded tothe plurality of first through vias; and attaching a second substrate tothe second side of the fingerprint sensor substrate, wherein the secondsubstrate is bonded to the plurality of second through vias.
 16. Themethod of claim 15, wherein the second substrate comprises an opening,and wherein a sidewall of the high voltage chip faces a sidewall of theopening.
 17. The method of claim 15, wherein the fingerprint sensorcover comprises sapphire or glass.
 18. The method of claim 15, whereinthe fingerprint sensor cover is attached to the first side of thefingerprint sensor substrate using a glue layer.
 19. The method of claim15, wherein the plurality of first through vias electrically couple thehigh voltage chip to the array of electrodes.
 20. The method of claim15, wherein the plurality of first through vias are interposed between afirst subset of the plurality of second through vias and a second subsetof the plurality of second through vias.